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Adjust the number of processes waiting on a semaphore properly if we're

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woken up in the middle of sleeping.

PR:		misc/64347
Reviewed by:	tjr
MFC after:	7 days
This commit is contained in:
Colin Percival 2004-03-17 09:37:13 +00:00
parent d67e2df265
commit 018e32c194
1 changed files with 12 additions and 6 deletions
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18
sys/kern/sysv_sem.c
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@ -1040,12 +1040,7 @@ semop(td, uap)
error = msleep(semaptr, sema_mtxp, (PZERO - 4) | PCATCH, error = msleep(semaptr, sema_mtxp, (PZERO - 4) | PCATCH,
"semwait", 0); "semwait", 0);
DPRINTF(("semop: good morning (error=%d)!\n", error)); DPRINTF(("semop: good morning (error=%d)!\n", error));
/* return code is checked below, after sem[nz]cnt-- */
if (error != 0) {
error = EINTR;
goto done2;
}
DPRINTF(("semop: good morning!\n"));
/* /*
* Make sure that the semaphore still exists * Make sure that the semaphore still exists
@ -1064,6 +1059,17 @@ semop(td, uap)
semptr->semzcnt--; semptr->semzcnt--;
else else
semptr->semncnt--; semptr->semncnt--;
/*
* Is it really morning, or was our sleep interrupted?
* (Delayed check of msleep() return code because we
* need to decrement sem[nz]cnt either way.)
*/
if (error != 0) {
error = EINTR;
goto done2;
}
DPRINTF(("semop: good morning!\n"));
} }
done: done: